Demand of a product for four years is shown below. Forecast demand for year five using following approaches:
1) a three - year moving avaerage.
2) a three-year weighted moving average using 0.40 for year 4, 0.20 for year 3 and 0.40 for year 2.
3) Exponential smooththing with alpha = 0.30, and assuming the forecast for period 1 = 68000.